Transformer Core Grounding Current Monitor IP66 MODBUS for Substation Protection

Transformer Core Grounding Current Monitor
 
Product Overview
 
During transformer operation, the combined effect of electric and magnetic fields generated by windings causes different potentials across various components of the iron core (including clamping pieces and other fittings). If the iron core is not grounded reliably, intermittent discharge may occur due to potential differences, damaging the insulation structure. In addition, multi-point grounding faults on the transformer iron core will form closed loops between every pair of grounding points via the iron core body and grounding cables. The alternating magnetic flux interlinking these loops induces circulating currents inside them, leading to local overheating of the iron core. In severe cases, local burnout may take place, posing a critical threat to the safe operation of the transformer.
 
 

Functions
 
(1) Continuously monitors the current values of the iron core grounding circuit and clamping pieces.
(2) Features maximum current memory function.
(3) Displays real-time current values, alarm current values and maximum recorded current values.
(4) Supports switching value alarm signal output.
(5) Alarm thresholds can be set locally or via the upper computer.
(6) Equipped with RS485 remote communication function.
(7) Comes with a 4-20mA instrument signal output interface.
 

Product Features
 
(1) This transformer core grounding current monitor measures currents ranging from 0 to 10A. It displays the peak current value and the maximum current recorded for each alarm event, helping users track the operating status of the transformer conveniently.
(2) For installation, the single turn of the main transformer’s core grounding down lead passes through the top opening of the monitor without modifying the original wiring of the tested transformer core. It introduces no safety hazards to in-service transformers. With strong immunity to external electromagnetic and electric field interference, the device delivers high measurement precision and accurate readings. It also features compact size, light weight and easy installation.
(3) The current monitor consists of a current sampling sensor, digital display, current measurement circuit, alarm circuit, standard signal output circuit and remote communication circuit. All circuit components comply with industrial grade standards and support a wide operating temperature range.
(4) Adopting a waterproof aluminum alloy enclosure with IP66 protection grade, the device can operate outdoors for long-term service.
 

Main Technical Parameters
 
1. Measured Object: Current of transformer iron core and clamping pieces
2. Measuring Range: AC 0~10A, resolution: 1mA
3. Digital Meter Measurement Error: ±1% of reading
4. Operating Power Supply: AC 220V ±15%
5. Withstand Voltage: 500V between primary (ground side) and secondary side (including circuit board)
6. Overload Capacity: 10 times of the maximum rated current
7. Operating Environment: Temperature -30~50°C, relative humidity less than 80%
8. Instrument Signal: 4~20mA two-wire system with built-in DC24V power supply
9. Communication Transmission Mode: MODBUS RTU (Remote Terminal Unit) mode
10. Communication Transmission Distance: 0~1000m
11. Communication Protocol: RS485 signal complying with Modbus protocol specifications
12. Output Capacity of Alarm Switch Signal: AC220V/7A, DC220V/1A
13. Housing Structure:
(1) Overall Dimensions: 200×150×80mm
(2) Weight: Approx. 2kg